Problem: In a list of $30$ integers, $18$ of the integers are multiples of $5$. If $10$ of the multiples of $5$ are odd integers, what is the maximum number of even integers in the list?
Explanation: Except for the $10$ multiples of $5$ which are odd, any of the integers on the list can be even, so we can have up to $30-10=\boxed{20}$ even integers.